This invention relates generally to the art of pipe networks for buildings and especially to apparatus and methods for embedding pipes in floors and walls and making fire-retardant pipe networks.
Until relatively recently, pipe networks were normally extended through floors of buildings by forming holes in the floors--e.g. by using void-forming devices during the "pouring" of the concrete floors, by knocking-out holes, by boring such holes after the floors had been formed, etc.--and thereafter extending pipes through these holes. Normally, the holes were made to be bigger than the pipes to ensure that one could easily extend pipes through the holes. Thereafter, it was necessary for workmen to fill the spaces between the pipes and the floors with cement or some other substance to meet fire codes which generally do not allowed holes in floors.
There have been a number of patents and other documents published, such as German Offenlegungsshrift 2,615,428, U.S. Pat. No. 4,453,354 to Harbeke, and U.S. Pat. No. 4,261,598 to Cornwall disclosing the concept of cementing pipe specialized coupling joints into floors when the floors are formed (sometimes called "cast-in couplings") and thereafter mating external pipes to opposite ends of the thusly embedded coupling joints. Difficulties with specialized pipe-coupling joints are that they are relatively expensive, they are sometimes difficult to cut to proper lengths for various concrete-floor thicknesses, and most of them do not prevent the spread of fire from a lower story to a higher story. It is an object of this invention to provide a device and method which allows one to construct an inexpensive "cast-in" coupling to be a proper length for a desired concrete-floor thickness which retards the spread of fire between stories. In this regard, it is an object of this invention to allow one to construct a cast-in coupler of standard pipe.
With regard to the "spread of fire", a major problem which still exists for plastic pipe-coupling joints which are embedded in floors is that when there is a fire, the fire melts external plastic pipes and then passes through embedded pipe coupling joints to the next higher floor. In other words, the embedded, or "cast-in" pipe coupling joints themselves serve as ventilation holes for fires. It has been suggested, and some fire codes require, that intumescent material surround plastic pipes where they pass through floor barriers. Upon being heated by a fire in the story below, such intumescent material swells, thereby compressing the plastic pipe closed at the floor barrier and preventing the fire from spreading through the floor barrier. Some of the specialized prior-art embedded pipe coupling joints have flanges at their bottom ends which are used to attach coupling joints to floor cement forms. Once the forms are removed these flanges serve as barriers to prevent heat from rising along outside surfaces of the joints to contact intumescent material wrapped thereabout and thereby delay the heating of the intumescent material and its swelling. Thus, it is a further object of this invention to provide a device and method for preparing an embedded pipe surrounded by intumescent material which is open to atmosphere from the story below so that it can quickly receive heat therefrom.
It has been suggested to attach cast-in pipe couplings to forms by means of separate attachment devices which must be removed before the forms are removed. Such devices are described in U.S. Pat. Nos. 4,619,087 and 4,642,956 to Gerold Harbeke. Other suggested devices hold pipes to forms by means of nails, screws and the like which, when the forms are removed, rip out of the form or the pipe. Such devices are described in U.S. Pat. No. 4,261,598 to Cornwall and in U.S. Pat. No. 4,619,471 to Harbeke. Such devices sometimes harm the form when they are removed and/or harm the pipe which must remain in the cement. A problem with both of these types of pipe attachment devices is that once the form is removed they are no longer properly attached to the form and cannot again be used to hold other pipes to the form for casting additional floors of a building. It is an object of this invention to provide a separate pipe attachment device and method which does not have to be removed from a form prior to the form being removed from cured concrete and which does not damage either the form or the pipe upon removal of the form from the cured concrete. Further, it is an object of this invention to provide a pipe attachment device and method which remains attached to the form when the form is removed, and is thereby a part of the form so that it can again be used for attaching pipes to the form when the form is used for casting additional floors.
It is yet another object of this invention to provide a pipe attachment device and method which can be used for making fire-retardant fluid couplings which act quickly enough to prevent a fire from spreading to the next higher story through a bore of the fluid coupling.
It is yet another object of this invention to provide a pipe attachment device for attaching pipes to concrete forms which is inexpensive to manufacture and use and which provides a great deal of flexibility in creating cast-in pipes.